EP0057004B1 - Flow measuring device - Google Patents

Flow measuring device Download PDF

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Publication number
EP0057004B1
EP0057004B1 EP82100489A EP82100489A EP0057004B1 EP 0057004 B1 EP0057004 B1 EP 0057004B1 EP 82100489 A EP82100489 A EP 82100489A EP 82100489 A EP82100489 A EP 82100489A EP 0057004 B1 EP0057004 B1 EP 0057004B1
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EP
European Patent Office
Prior art keywords
throttle member
measuring device
flow
housing
throttle
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
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EP82100489A
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German (de)
French (fr)
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EP0057004A1 (en
Inventor
Roger John Nelson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Deere and Co
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Deere and Co
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Publication date
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Priority to AT82100489T priority Critical patent/ATE16733T1/en
Publication of EP0057004A1 publication Critical patent/EP0057004A1/en
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Publication of EP0057004B1 publication Critical patent/EP0057004B1/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
    • G01F1/22—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow by variable-area meters, e.g. rotameters
    • G01F1/24—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow by variable-area meters, e.g. rotameters with magnetic or electric coupling to the indicating device
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/05—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects
    • G01F1/20—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow
    • G01F1/22—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using mechanical effects by detection of dynamic effects of the flow by variable-area meters, e.g. rotameters

Definitions

  • Such an embodiment can e.g. see the patents US-A 3528288 and US-A 3623046.
  • housing shoulders directed away from one another are provided, against each of which a disk-shaped bearing rests, which has flow openings and serves to hold a rod located centrally in the flow channel.
  • the first throttle body is slidably mounted, on the opposite ends of which a centering spring engages, which coaxially surrounds the rod and is supported with its other end on the associated disk-shaped bearing.
  • This displaceable first throttle body interacts with a stationary second throttle body, which is formed by the wall of the flow channel and consists of an annular diaphragm, the cross section of which has the shape of a flat isosceles triangle.
  • the displaceable first throttle body is designed in the form of a cutting edge in its central section, the cutting edge being opposite the triangular tip of the said ring diaphragm of the second throttle body in the neutral position of the throttle body.
  • the housing of this known flow measuring device has an outer casing made of magnetic material, which encloses an inner casing made of non-magnetic material. Coils are embedded in the latter and are part of the above-mentioned measuring device for generating an output signal.
  • the respective symmetrical shape of the two throttle bodies can be designed in such a way that linear output values result.
  • the flow measuring device explained above can be used for this purpose, which generates an electrical signal that represents the flow flow and has a linear relationship with the respective flow rate. With this flow measuring device, the hydraulic flow can be measured in both directions with relatively little effort.
  • the invention has for its object to improve the responsiveness of the flow measuring device explained above.
  • the displaceable throttle body is sleeve-shaped, encloses the stationary first throttle body and consists of magnetically conductive material, and that two abutments are arranged on the stationary throttle body, each of which then one of the two resilient members uncouple the displaceable throttle body when it is shifted from its neutral position towards the other of the two resilient members.
  • the device according to the invention achieves that when the sleeve-shaped throttle body is displaced in one direction or the other only one of the two springs exerts a force on the throttle body.
  • the displaceable throttle body forms a sleeve-shaped core, which is separated from the measuring device only by the housing wall, so that there is a high magnetic flux between the displaceable core and said measuring device.
  • the bidirectional flow measuring device 10 shown consists of a housing 12 made of non-magnetic material, for example of non-magnetic, corrosion-resistant steel.
  • the housing 12 has a stepped bore 14 which forms a housing shoulder 16 and a passage 18.
  • An end connection piece 20 is screwed into the housing 12 and has a passage 22 and a second housing shoulder 24.
  • An O-ring 26, a clamping nut 28 and a washer 30 are provided as a liquid seal between the end connector 20 and the housing 12. Between the passages 18, 22, the liquid flow can flow through the bore 14 in both directions.
  • a rod-shaped, axially symmetrical throttle body 32 is arranged centrally and coaxially, which has two end parts 34, 36 of smaller diameter, which pass over shoulders 40, 42 into a central part of larger, but not constant, diameter.
  • This central part 38 has an outwardly projecting cutting edge 39 which slowly and symmetrically widens from the largest diameter in its center to a constant diameter section next to the shoulders 40, 42 mentioned.
  • the end parts 34, 36 of the rod-shaped throttle body 32 are held in two identically designed bearings 50 and protrude here into the bore of a cylindrical central section 52, which merges into a flange 54, which on the one hand on the inner wall of the bore 14 and on the associated housing shoulder 24 and 16 is present.
  • Each flange 54 has a conical section through which six through-openings 56, which are arranged at the same distance from one another, extend, the central axes of which form an angle of 30 ° with the longitudinal axis of the rod-shaped throttle body 32 (in the drawing only 56 of the six through-openings 56 are in each case two openings shown).
  • an abutment 60 is provided with openings, which has three radially extending arms 61, two of which can be seen in the drawing shown. Between the abutments 60 and the shoulders 40, 42, intermediate rings are provided, so that the rod-shaped throttle body 32, the abutment 60 and the bearings 50 are arranged in the axial direction between the housing shoulders 24, 16.
  • annular diaphragm 74 protrudes radially inward from the triangular cross-section and forms a variable throttle cross-section with the cutting edge 39 of the stationary throttle body 32, depending on the axial displacement position of the sleeve-shaped throttle body 66 relative to the rod-shaped throttle body 32.
  • the core is located forming displaceable throttle body 66 in its neutral position shown in the drawing, there is a narrow annular gap between the annular diaphragm 74 and the cutting edge 39.
  • Diaphragm 74 and cutting edge 39 are shaped such that there is a linear displacement of throttle body 66 as a function of the flow rate.
  • the flow measuring device 10 further comprises two identically designed cylindrical guide pieces 80, each of which has a cylindrical section 82 of smaller diameter, which slidably engages in the end of the displaceable sleeve-shaped throttle body 66, while a shoulder 84 or an annular end face of the cylindrical guide piece on the arms 61 of the associated abutment 60 is present.
  • Each guide piece 80 further comprises a cylindrical section 86 of larger diameter, which overlaps one end of an associated centering spring 88 or 90, which is supported on an annular shoulder 94 of the guide piece 80. The latter rests with an annular shoulder 92 on the adjacent end of the displaceable throttle body 66.
  • centering springs 88, 90 are supported with their other ends on the respectively associated bearing 50 and press the displaceable throttle body 66 via the guide pieces 80 into its neutral position shown in the drawing relative to the stationary throttle body 32 or the housing 12, if through the bore 14 no flow flows. Both centering springs 88, 90 are slightly pretensioned when the displaceable throttle body 66 is in its neutral position, so that the centering of the displaceable throttle body 66 is ensured despite existing friction losses.
  • the respective axial displacement position of the throttle body 66 can be determined by a customary linearly variable differential transformer (LVDT), which can have a cylindrical LVDT coil arrangement 100, as is e.g. is manufactured by Schaevitz Engineering, Camden, New Jersey, and which can be mounted coaxially on the outer surface of the non-magnetic housing 12.
  • LVDT linearly variable differential transformer
  • Conventional electrical circuitry may be connected to the coil assembly 100 (as described, for example, on pages 17-55 and 17-56 in DG Fink's Electronics Engineers Handbook, McGraw-Hill, 1975) to produce an electrical output signal which indicates axial displacement position of the throttle body 66 relative to the coil assembly 100.
  • the flow measuring device works as follows: If no liquid flows through the bore 14, the centering springs 88, 90 hold the displaceable throttle body 66 in its neutral position. On the other hand, liquid flows through the bore 14, the throttle body 66 is displaced by its liquid flow from its neutral position in the direction of the liquid flow, by an amount that is proportional to the flow rate. If the liquid flows in the illustrated embodiment, for example to the right, the throttle body 66 is shifted to the right and thereby compresses the centering spring 90 until the forces exerted by the flowing liquid are in equilibrium with the increasing force of the spring 90.
  • the centering spring 88 is decoupled from the throttle body 66, so that the latter is only acted upon by one of the centering springs 88 or 90 when it is shifted to the left or right out of its neutral position.
  • the coil arrangement 100 and the LVDT circuit (not shown) operate in a conventional manner and generate output signals which represent the direction and size of the displacement of the throttle body 66 and thus the direction and size of the flow flow through the bore 14.

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)
  • Indicating Or Recording The Presence, Absence, Or Direction Of Movement (AREA)

Description

Die Erfindung betrifft eine Zweirichtungs-Strömungsmesseinrichtung, bestehend aus

  • - einem nicht-magnetischen Gehäuse, das einen Strömungskanal für eine Zweirichtungsströmung umschliesst;
  • - einem ersten Drosselkörper, der im Strömungskanal angeordnet ist und mit einem im Abstand von ihm angeordneten zweiten Drosselkörper einen veränderbaren Drosselquerschnitt bildet, wobei einer der beiden Drosselkörper gegenüber dem anderen dieser beiden Drosselkörper so verschiebbar ist, dass er bei nicht vorhandener Strömung seine Neutralstellung einnimmt, unter der Wirkung einer Strömung aber aus dieser Neutralstellung in Strömungsrichtung um ein Mass verschoben wird, das die jeweilige Durchflussmenge angibt, und wobei einer der beiden Drosselkörper hülsenförmig ausgebildet ist und den anderen Drosselkörper umschliesst;
  • - zwei federelastischen Gliedern, die an gegenüberliegenden Enden des verschiebbaren Drosselkörpers angreifen und diesen in seine Neutralstellung drücken;
  • - einer das Gehäuse koaxial umschliessenden Messeinrichtung in Form eines induktiv arbeitenden Verschiebungswandlers zur Erzeugung eines Ausgangssignals, das die jeweilige Stellung des verschiebbaren Drosselkörpers angibt.
The invention relates to a bidirectional flow measuring device consisting of
  • - a non-magnetic housing which encloses a flow channel for a bidirectional flow;
  • a first throttle body which is arranged in the flow channel and forms a variable throttle cross-section with a second throttle body arranged at a distance therefrom, one of the two throttle bodies being displaceable relative to the other of these two throttle bodies in such a way that it assumes its neutral position when there is no flow, under the action of a flow but is shifted from this neutral position in the direction of flow by a measure that indicates the respective flow rate, and wherein one of the two throttle bodies is sleeve-shaped and encloses the other throttle body;
  • - Two resilient links which engage at opposite ends of the displaceable throttle body and press it into its neutral position;
  • - A measuring device coaxially enclosing the housing in the form of an inductively operating displacement transducer for generating an output signal which indicates the respective position of the displaceable throttle body.

Eine derartige Ausführungsform lässt sich z.B. den Patentschriften US-A 3528288 und US-A 3623046 entnehmen. Im Bereich der beiden Enden des Strömungskanals sind voneinander weg gerichtete Gehäuseschultern vorgesehen, gegen die jeweils ein scheibenförmig ausgebildetes Lager anliegt, das Durchströmöffnungen aufweist und zur Halterung einer zentrisch im Strömungskanal liegenden Stange dient. Auf dieser ist der erste Drosselkörper verschiebbar gelagert, an dessen sich gegenüberliegenden Enden jeweils eine Zentrierfeder angreift, die die genannte Stange koaxial umschliesst und sich mit ihrem anderen Ende an dem zugeordneten scheibenförmigen Lager abstützt. Dieser verschiebbare erste Drosselkörper wirkt mit einem stationären zweiten Drosselkörper zusammen, der durch die Wandung des Strömungskanals gebildet wird und aus einer ringförmigen Blende besteht, deren Querschnitt die Form eines flachen gleichschenkligen Dreiecks aufweist. Der verschiebbare erste Drosselkörper ist in seinem mittleren Abschnitt schneidenförmig ausgebildet, wobei die Schneide in der Neutralstellung des Drosselkörpers der Dreiecksspitze der genannten Ringblende des zweiten Drosselkörpers gegenüberliegt.Such an embodiment can e.g. see the patents US-A 3528288 and US-A 3623046. In the region of the two ends of the flow channel, housing shoulders directed away from one another are provided, against each of which a disk-shaped bearing rests, which has flow openings and serves to hold a rod located centrally in the flow channel. On this, the first throttle body is slidably mounted, on the opposite ends of which a centering spring engages, which coaxially surrounds the rod and is supported with its other end on the associated disk-shaped bearing. This displaceable first throttle body interacts with a stationary second throttle body, which is formed by the wall of the flow channel and consists of an annular diaphragm, the cross section of which has the shape of a flat isosceles triangle. The displaceable first throttle body is designed in the form of a cutting edge in its central section, the cutting edge being opposite the triangular tip of the said ring diaphragm of the second throttle body in the neutral position of the throttle body.

Das Gehäuse dieser vorbekannten Strömungsmesseinrichtung weist einen äusseren Mantel aus magnetischem Material auf, der einen inneren Gehäusemantel aus nicht-magnetischem Material umschliesst. In letzterem sind Spulen eingebettet, die Teil der vorstehend erwähnten Messeinrichtung zur Erzeugung eines Ausgangssignals sind. Die jeweils symmetrische Form der beiden Drosselkörper kann so ausgebildet sein, dass sich lineare Ausgangswerte ergeben.The housing of this known flow measuring device has an outer casing made of magnetic material, which encloses an inner casing made of non-magnetic material. Coils are embedded in the latter and are part of the above-mentioned measuring device for generating an output signal. The respective symmetrical shape of the two throttle bodies can be designed in such a way that linear output values result.

Es ist üblich geworden, Hydraulikkreise elektronisch zu steuern, wobei es oft wünschenswert ist, die Hydraulikdurchflussmenge durch einen bestimmten Abschnitt des Hydraulikkreises festzustellen. Hierfür lässt sich die vorstehend erläuterte Strömungsmesseinrichtung verwenden, die ein elektrisches Signal erzeugt, das den Strömungsfluss darstellt und einen linearen Zusammenhang mit der jeweiligen Durchflussmenge aufweist. Mit dieser Strömungsmesseinrichtung lässt sich die Hydraulikströmung in beiden Richtungen mit verhältnismässig geringem Aufwand messen.It has become common to control hydraulic circuits electronically, and it is often desirable to determine the hydraulic flow rate through a particular portion of the hydraulic circuit. The flow measuring device explained above can be used for this purpose, which generates an electrical signal that represents the flow flow and has a linear relationship with the respective flow rate. With this flow measuring device, the hydraulic flow can be measured in both directions with relatively little effort.

Der Erfindung liegt die Aufgabe zugrunde, die Ansprechempfindlichkeit der eingangs erläuterten Strömungsmesseinrichtung zu verbessern.The invention has for its object to improve the responsiveness of the flow measuring device explained above.

Diese Aufgabe wird gemäss der Erfindung dadurch gelöst, dass der verschiebbare Drosselkörper hülsenförmig ausgebildet ist, den stationären ersten Drosselkörper umschliesst und aus magnetisch leitfähigem Material besteht, und dass auf dem stationären Drosselkörper zwei Widerlager angeordnet sind, die jeweils das eine der beiden federelastischen Glieder dann von dem verschiebbaren Drosselkörper abkuppeln, wenn dieser aus seiner Neutralstellung in Richtung auf das andere der beiden federelastischen Glieder verschoben wird.This object is achieved according to the invention in that the displaceable throttle body is sleeve-shaped, encloses the stationary first throttle body and consists of magnetically conductive material, and that two abutments are arranged on the stationary throttle body, each of which then one of the two resilient members uncouple the displaceable throttle body when it is shifted from its neutral position towards the other of the two resilient members.

Während bei der eingangs beschriebenen, vorbekannten Strömungsmesseinrichtung der verschiebbare Drosselkörper ständig unter der Wirkung beider Druckfedern steht, die zur Kompensation der entsprechenden Verschiebungswege eine ausreichende Vorspannung benötigen, wird bei der erfindungsgemässen Einrichtung erreicht, dass bei einer Veschiebung des hülsenförmigen Drosselkörpers in die eine oder andere Richtung immer nur eine der beiden Federn eine Kraft auf den Drosselkörper ausübt.While in the known flow measuring device described at the outset, the displaceable throttle body is constantly under the action of both compression springs, which require sufficient pretension to compensate for the corresponding displacement paths, the device according to the invention achieves that when the sleeve-shaped throttle body is displaced in one direction or the other only one of the two springs exerts a force on the throttle body.

Der verschiebbare Drosselkörper bildet einen hülsenförmigen Kern, der von der Messeinrichtung lediglich durch die Gehäusewandung getrennt ist, so dass sich ein hoher magnetischer Fluss zwischen dem verschiebbaren Kern und der genannten Messeinrichtung ergibt. Hierdurch sowie durch die Ausbildung des verschiebbaren Drosselkörpers als Hülse ergeben sich verbesserte Effizienz und höhere Ansprechempfindlichkeit.The displaceable throttle body forms a sleeve-shaped core, which is separated from the measuring device only by the housing wall, so that there is a high magnetic flux between the displaceable core and said measuring device. This, as well as the design of the displaceable throttle body as a sleeve, results in improved efficiency and greater responsiveness.

Neugestaltungen der Erfindung sind Gegenstand der abhängigen Ansprüche und werden nachfolgend zusammen mit weiteren Vorteilen der Erfindung anhand eines Ausführungsbeispiels näher erläutert.Redesigns of the invention are the subject of the dependent claims and are explained below together with further advantages of the invention using an exemplary embodiment.

In der Zeichnung ist eine als Beispiel dienende Ausführungsform der Erfindung im Längsschnitt dargestellt. Die dargestellte Zweirichtungs-Strömungsmesseinrichtung 10 besteht aus einem Gehäuse 12 aus nicht-magnetischem Material, z.B. aus unmagnetischem korrosionsbeständigem Stahl. Das Gehäuse 12 weist eine abgesetzte Bohrung 14 auf, die eine Gehäuseschulter 16 sowie einen Durchlass 18 bildet. In das andere Ende des Gehäuses 12 ist ein Endverbundstück 20 eingeschraubt, das einen Durchlass 22 und eine zweite Gehäuseschulter 24 aufweist. Zwischen Endverbundstück 20 und Gehäuse 12 sind als Flüssigkeitsdichtung ein O-Ring 26, eine Klemmmutter 28 sowie eine Scheibe 30 vorgesehen. Zwischen den Durchlässen 18, 22 kann die Flüssigkeitsströmung in beiden Richtungen durch die Bohrung 14fliessen.In the drawing, an exemplary embodiment of the invention is shown in longitudinal section. The bidirectional flow measuring device 10 shown consists of a housing 12 made of non-magnetic material, for example of non-magnetic, corrosion-resistant steel. The housing 12 has a stepped bore 14 which forms a housing shoulder 16 and a passage 18. In the other end An end connection piece 20 is screwed into the housing 12 and has a passage 22 and a second housing shoulder 24. An O-ring 26, a clamping nut 28 and a washer 30 are provided as a liquid seal between the end connector 20 and the housing 12. Between the passages 18, 22, the liquid flow can flow through the bore 14 in both directions.

In der Bohrung 14 ist zentrisch und koaxial ein stangenförmiger, axial symmetrisch ausgebildeter Drosselkörper 32 angeordnet, der zwei Endteile 34, 36 kleineren Durchmessers aufweist, die über Schultern 40, 42 in einen Mittelteil grösseren, jedoch nicht gleichbleibenden Durchmessers übergehen. Dieser Mittelteil 38 weist eine nach aussen ragende Schneide 39 auf, die sich langsam und symmetrisch gleichmässig von einem grössten Durchmesser in ihrer Mitte zu einem gleichbleibenden Durchmesserabschnitt neben den genannten Schultern 40, 42 verbreitert.In the bore 14, a rod-shaped, axially symmetrical throttle body 32 is arranged centrally and coaxially, which has two end parts 34, 36 of smaller diameter, which pass over shoulders 40, 42 into a central part of larger, but not constant, diameter. This central part 38 has an outwardly projecting cutting edge 39 which slowly and symmetrically widens from the largest diameter in its center to a constant diameter section next to the shoulders 40, 42 mentioned.

Die Endteile 34, 36 des stangenförmigen Drosselkörpers 32 sind in zwei identisch ausgebildeten Lagern 50 gehalten und ragen hier in die Bohrung eines zylindrischen Zentralabschnitts 52, der in einen Flansch 54 übergeht, der einerseits an der Innenwandung der Bohrung 14 sowie an der zugeordneten Gehäuseschulter 24 bzw. 16 anliegt. Jeder Flansch 54 weist einen konischen Abschnitt auf, durch den sich sechs im gleichen Abstand voneinander angeordnete Durchströmöffnungen 56 erstrecken, deren Mittelachsen mit der Längsachse des stangenförmigen Drosselkörpers 32 einen Winkel von 30° einschliessen (in der Zeichnung sind von den jeweils sechs Durchströmöffnungen 56 nur jeweils zwei Öffnungen dargestellt).The end parts 34, 36 of the rod-shaped throttle body 32 are held in two identically designed bearings 50 and protrude here into the bore of a cylindrical central section 52, which merges into a flange 54, which on the one hand on the inner wall of the bore 14 and on the associated housing shoulder 24 and 16 is present. Each flange 54 has a conical section through which six through-openings 56, which are arranged at the same distance from one another, extend, the central axes of which form an angle of 30 ° with the longitudinal axis of the rod-shaped throttle body 32 (in the drawing only 56 of the six through-openings 56 are in each case two openings shown).

Auf den Endteilen 34, 36 des stangenförmigen Drosselkörpers 32 ist zwischen dem zentrischen Abschnitt 52 des Lagers 50 sowie der Schulter 40 bzw. 42 des Drosselkörpers 32 jeweils ein mit Durchbrechungen versehenes Widerlager 60 angeordnet, das drei sich radial erstreckende Arme 61 aufweist, von denen zwei in der dargestellten Zeichnung erkennbar sind. Zwischen den Widerlagern 60 und den Schultern 40, 42 sind Zwischenringe vorgesehen, so dass der stangenförmige Drosselkörper 32, die Widerlager 60 sowie die Lager 50 in axialer Richtung fest zwischen den Gehäuseschultern 24, 16 angeordnet sind.On the end parts 34, 36 of the rod-shaped throttle body 32 between the central portion 52 of the bearing 50 and the shoulder 40 and 42 of the throttle body 32, an abutment 60 is provided with openings, which has three radially extending arms 61, two of which can be seen in the drawing shown. Between the abutments 60 and the shoulders 40, 42, intermediate rings are provided, so that the rod-shaped throttle body 32, the abutment 60 and the bearings 50 are arranged in the axial direction between the housing shoulders 24, 16.

In der Bohrung 14 ist ein den stationären Drosselkörper 32 mit Abstand koaxial umschliessender Drosselkörper 66 in Form einer axial symmetrischen Hülse aus magnetischem Material verschiebbar gelagert. Dieser verschiebbare Drosselkörper 66 bildet in elektromagnetischer Hinsicht einen Kern, der Endflansche 68, 70 grösseren Durchmessers sowie einen zylindrischen Mittelteil 72 kleineren Durchmessers aufweist und mit den äusseren Mantelflächen der Endflansche 68, 70 an der die Bohrung 14 bildenden Wandung verschiebbar geführt ist. Vom Mittelteil 72 ragt eine ringförmige Blende 74 vom dreiecksförmigen Querschnitt radial nach innen und bildet mit der Schneide 39 des stationären Drosselkörpers 32 einen veränderbaren Drosselquerschnitt, und zwar je nach axialer Verschiebestellung des hülsenförmigen Drosselkörpers 66 relativ gegenüber dem stangenförmigen Drosselkörper 32. Befindet sich der den Kern bildende verschiebbare Drosselkörper 66 in seiner in der Zeichnung dargestellten Neutralstellung, besteht zwischen der ringförmigen Blende 74 und der Schneide 39 ein schmaler Ringspalt. Blende 74 und Schneide 39 sind so geformt, dass sich eine lineare Verschiebung des Drosselkörpers 66 als Funktion der Durchflussmenge ergibt.In the bore 14 is a stationary throttle body 32 coaxially enclosing throttle body 66 in the form of an axially symmetrical sleeve made of magnetic material. From an electromagnetic point of view, this displaceable throttle body 66 forms a core which has end flanges 68, 70 of larger diameter and a cylindrical middle part 72 of smaller diameter and is displaceably guided with the outer lateral surfaces of end flanges 68, 70 on the wall forming bore 14. From the central part 72, an annular diaphragm 74 protrudes radially inward from the triangular cross-section and forms a variable throttle cross-section with the cutting edge 39 of the stationary throttle body 32, depending on the axial displacement position of the sleeve-shaped throttle body 66 relative to the rod-shaped throttle body 32. The core is located forming displaceable throttle body 66 in its neutral position shown in the drawing, there is a narrow annular gap between the annular diaphragm 74 and the cutting edge 39. Diaphragm 74 and cutting edge 39 are shaped such that there is a linear displacement of throttle body 66 as a function of the flow rate.

Die Strömungsmesseinrichtung 10 umfasst ferner zwei identisch ausgebildete zylindrische Führungsstücke 80, von denen jedes einen zylindrischen Abschnitt 82 kleineren Durchmessers aufweist, der in das Ende des verschiebbaren hülsenförmigen Drosselkörpers 66 gleitend eingreift, während eine Schulter 84 bzw. eine ringförmige Stirnfläche des zylindrischen Führungsstücks an den Armen 61 des zugeordneten Widerlagers 60 anliegt. Jedes Führungsstück 80 umfasst ferner einen zylindrischen Abschnitt 86 grösseren Durchmessers, der das eine Ende einer zugeordneten Zentrierfeder 88 bzw. 90 übergreift, die sich an einer ringförmigen Schulter 94 des Führungsstücks 80 abstützt. Letzteres liegt mit einer Ringschulter 92 an dem benachbarten Ende des verschiebbaren Drosselkörpers 66 an. Die Zentrierfedern 88, 90 stützen sich mit ihren anderen Enden an dem jeweils zugeordneten Lager 50 ab und drücken den verschiebbaren Drosselkörper 66 über die Führungsstücke 80 in seine in der Zeichnung dargestellte Neutralstellung gegenüber dem stationären Drosselkörper 32 bzw. dem Gehäuse 12, wenn durch die Bohrung 14 keine Strömung fliesst. Beide Zentrierfedem 88, 90 sind leicht vorgespannt, wenn sich der verschiebbare Drosselkörper 66 in seiner Neutralstellung befindet, so dass die Zentrierung des verschiebbaren Drosselkörpers 66 trotz bestehender Reibungsverluste sichergestellt ist.The flow measuring device 10 further comprises two identically designed cylindrical guide pieces 80, each of which has a cylindrical section 82 of smaller diameter, which slidably engages in the end of the displaceable sleeve-shaped throttle body 66, while a shoulder 84 or an annular end face of the cylindrical guide piece on the arms 61 of the associated abutment 60 is present. Each guide piece 80 further comprises a cylindrical section 86 of larger diameter, which overlaps one end of an associated centering spring 88 or 90, which is supported on an annular shoulder 94 of the guide piece 80. The latter rests with an annular shoulder 92 on the adjacent end of the displaceable throttle body 66. The centering springs 88, 90 are supported with their other ends on the respectively associated bearing 50 and press the displaceable throttle body 66 via the guide pieces 80 into its neutral position shown in the drawing relative to the stationary throttle body 32 or the housing 12, if through the bore 14 no flow flows. Both centering springs 88, 90 are slightly pretensioned when the displaceable throttle body 66 is in its neutral position, so that the centering of the displaceable throttle body 66 is ensured despite existing friction losses.

Die jeweilige axiale Verschiebungsstellung des Drosselkörpers 66 lässt sich durch einen üblichen linear veränderlichen Differentialtransformator (LVDT) feststellen, der eine zylindrische LVDT-Spulenanordnung 100 aufweisen kann, wie sie z.B. hergestellt wird von Schaevitz Engineering, Camden, New Jersey, und die koaxial auf die äussere Mantelfläche des nicht-magnetischen Gehäuses 12 montiert sein kann. An die Spulenanordnung 100 kann eine übliche elektrische Schaltung angeschlossen sein (wie sie z.B. beschrieben ist auf den Seiten 17-55 und 17-56 in D.G. Fink's Electronics Engineers Handbook, McGraw-Hill, 1975), um ein elektrisches Ausgangssignal zu erzeugen, das die axiale Verschiebestellung des Drosselkörpers 66 relativ gegenüber der Spulenanordnung 100 angibt.The respective axial displacement position of the throttle body 66 can be determined by a customary linearly variable differential transformer (LVDT), which can have a cylindrical LVDT coil arrangement 100, as is e.g. is manufactured by Schaevitz Engineering, Camden, New Jersey, and which can be mounted coaxially on the outer surface of the non-magnetic housing 12. Conventional electrical circuitry may be connected to the coil assembly 100 (as described, for example, on pages 17-55 and 17-56 in DG Fink's Electronics Engineers Handbook, McGraw-Hill, 1975) to produce an electrical output signal which indicates axial displacement position of the throttle body 66 relative to the coil assembly 100.

Die Arbeitsweise der Strömungsmesseinrichtung ist wie folgt: Fliesst keine Flüssigkeit durch die Bohrung 14, halten die Zentrierfedern 88, 90 den verschiebbaren Drosselkörper 66 in seiner Neutralstellung. Fliesst hingegen Flüssigkeit durch die Bohrung 14, so wird der Drosselkörper 66 durch diesen Flüssigkeitsstrom aus seiner Neutralstellung in Richtung der Flüssigkeitsströmung verschoben, und zwar um einen Betrag, der der Durchströmmenge proportional ist. Strömt bei dem dargestellten Ausführungsbeispiel die Flüssigkeit z.B. nach rechts, wird der Drosselkörper 66 nach rechts verschoben und drückt dabei die Zentrierfeder 90 so weit zusammen, bis die durch die strömende Flüssigkeit ausgeübten Kräfte mit der zunehmenden Kraft der Feder 90 im Gleichgewicht stehen. Bewegt sich der Drosselkörper 66 aus einer Neutralstellung nach rechts, legt sich die ringförmige Stirnfläche 84 des in der Zeichnung links liegenden Führungsstücks 80 gegen das benachbarte Widerlager 60 an und verhindert dadurch, dass sich das linke Führungsstück 80 zusammen mit dem verschiebbaren Drosselkörper 66 nach rechts bewegt. Hierdurch wird die Zentrierfeder 88 von dem Drosselkörper 66 abgekoppelt, so dass letzterer bei seiner Verschiebung nach links oder rechts aus seiner Neutralstellung heraus immer nur von einer der Zentrierfedern 88 oder 90 beaufschlagt wird.The flow measuring device works as follows: If no liquid flows through the bore 14, the centering springs 88, 90 hold the displaceable throttle body 66 in its neutral position. On the other hand, liquid flows through the bore 14, the throttle body 66 is displaced by its liquid flow from its neutral position in the direction of the liquid flow, by an amount that is proportional to the flow rate. If the liquid flows in the illustrated embodiment, for example to the right, the throttle body 66 is shifted to the right and thereby compresses the centering spring 90 until the forces exerted by the flowing liquid are in equilibrium with the increasing force of the spring 90. If the throttle body 66 moves from a neutral position to the right, the annular end face 84 of the guide piece 80 on the left in the drawing rests against the adjacent abutment 60 and thereby prevents the left guide piece 80 from moving to the right together with the displaceable throttle body 66 . As a result, the centering spring 88 is decoupled from the throttle body 66, so that the latter is only acted upon by one of the centering springs 88 or 90 when it is shifted to the left or right out of its neutral position.

Die Spulenanordnung 100 sowie die nicht dargestellte LVDT-Schaltung arbeiten in herkömmlicher Weise und erzeugen Ausgangssignale, die Richtung und Grösse der Verschiebung des Drosselkörpers 66 und damit Richtung und Grösse des Strömungsflusses durch die Bohrung 14 darstellen.The coil arrangement 100 and the LVDT circuit (not shown) operate in a conventional manner and generate output signals which represent the direction and size of the displacement of the throttle body 66 and thus the direction and size of the flow flow through the bore 14.

Claims (11)

1. A bi-directional flow measuring device (10) comprising:
- a non-magnetic housing (12, 20) surrounding a flow passage (18,14,22) for a bi-directional flow;
- a first throttle member (32) arranged in the flow passage (18, 14, 22) and a second throttle member (66) spaced apart from said first throttle member to form a variable throttle cross-section, one of both throttle members (32, 66) being movable relative to the other throttle member in such a way that it takes its neutral position in the absence of flow; in response to fluid flow, however, said throttle member is displaced from said neutral position in the direction of fluid flow by an amount indicating the respective rate of fluid flow, and whereby one of both throttle members has the shape of a cylindrical sleeve and surrounds the other throttle member;
- two resilient members (88, 90) acting upon opposite ends of the movable throttle member (66) and urging said throttle member (66) to its neutral position;
- sensing means (100) for generating an output signal indicating the respective position of the movable throttle member (66), said sensing means surrounding coaxially the housing (12) and being in the form of an inductively working displacement transducer; characterized in that the movable throttle member (66) has the shape of a cylindrical sleeve surrounding the fixed first throttle member (32) and is of magnetic conductive material, and that two abutment members (60) are arranged on the fixed throttle member (32) and then uncouple the respective resilient member (88,90) from the movable throttle member (66) when the movable throttle member is displaced from its neutral position towards the other resilient member.
2. The flow measuring device according to claim 1, wherein said movable throttle member (66) has a portion (72) of a smaller diameter and further has two ring portions (68, 70) of a larger diameter, the outer peripheral surface of the larger outer diameter ring portions slidably engaging the housing (12).
3. The flow measuring device according to one of the preceding claims, wherein the movable throttle member (66) coaxially surrounds said fixed throttle member (32) mounted centrally in the flow passage and having the shape of a rod.
4. The flow measuring device according to claim 3, wherein the fixed throttle member (32) comprises a middle portion (38) having a larger diameter and being interconnected on its end portions with smaller diameter portions (34, 36) by a pair of annular shoulders (40, 42), the abutment members (60) being supported by said smaller diameter portions and engaging the annular shoulders (40,42).
5. The flow measuring device according to one of the preceding claims, wherein each end portion of said fixed throttle member (32) projects in a central bore of a pair of support members (50) in the flow passage (14), whereby each support member has a generally radially extending flange (54) engaging the housing (12, 20) and having apertures (56) for permitting fluid flow therethrough.
6. The flow measuring device according to claim 5, wherein said flange (54) of each support member (50) comprises a conical portion, the apertures (56) for fluid flow being arranged in said conical portion.
7. The flow measuring device according to claim 5 or 6, wherein the middle axes of said apertures (56) form an acute angle with the longitudinal axis of the fixed throttle member (32).
8. The flow measuring device according to claim 5, or 7, wherein the cylindrical middle portion (52) of each support member (50) urges the corresponding abutment member (60) against the shoulder (40, 42) of said fixed throttle member (32).
9. The flow measuring device according to one of the claims 2 to 8, wherein each resilient member comprises a centering spring (88, 90) coaxially surrounding the end portion (34,36) of the fixed throttle member (32), and further comprises a cylindrical guide member (80) having a first shoulder (94) supporting the centering spring (88, 90), a second shoulder (92) engageable with the movable throttle member (66) and a third shoulder (84) engageable with the corresponding abutment member (60).
10. The flow measuring device according to claim 9, wherein each of the two cylindrical guide members (80) has a smaller diameter cylindrical portion (82) slidably engaging the ends of the movable cylindrical throttle member (66).
11. The flow measuring device according to one of the preceding claims, wherein said housing (12,20) surrounds with a wall a bore (14) forming the flow passage, the housing having oppositely facing housing shoulders (16, 24) located in the area of the ends of the flow passage, the flange (54) of each support member (50) engaging a corresponding one of said housing shoulders, whereby the abutment members (60) and the support members (50) cooperate in such a way with the housing (12, 20), the housing shoulders (16, 24) and the annular shoulders (40, 42) of the fixed throttle member (32) that the fixed throttle member is held in a central position in said bore (14) and fixed with respect to the housing.
EP82100489A 1981-01-26 1982-01-25 Flow measuring device Expired EP0057004B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82100489T ATE16733T1 (en) 1981-01-26 1982-01-25 FLOW MEASUREMENT DEVICE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US228437 1981-01-26
US06/228,437 US4366718A (en) 1981-01-26 1981-01-26 Bi-directional flow transducer

Publications (2)

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EP0057004A1 EP0057004A1 (en) 1982-08-04
EP0057004B1 true EP0057004B1 (en) 1985-11-27

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EP82100489A Expired EP0057004B1 (en) 1981-01-26 1982-01-25 Flow measuring device

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US (1) US4366718A (en)
EP (1) EP0057004B1 (en)
JP (1) JPS57142517A (en)
AR (1) AR243278A1 (en)
AT (1) ATE16733T1 (en)
AU (1) AU545441B2 (en)
BR (1) BR8200236A (en)
CA (1) CA1170478A (en)
DE (1) DE3267638D1 (en)
ES (1) ES8303687A1 (en)
MX (1) MX156443A (en)
ZA (1) ZA82476B (en)

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Also Published As

Publication number Publication date
ES509031A0 (en) 1983-02-01
ZA82476B (en) 1983-09-28
AU545441B2 (en) 1985-07-11
JPS57142517A (en) 1982-09-03
ATE16733T1 (en) 1985-12-15
MX156443A (en) 1988-08-23
CA1170478A (en) 1984-07-10
JPH034845B2 (en) 1991-01-24
ES8303687A1 (en) 1983-02-01
DE3267638D1 (en) 1986-01-09
EP0057004A1 (en) 1982-08-04
AR243278A1 (en) 1993-07-30
BR8200236A (en) 1982-11-09
US4366718A (en) 1983-01-04
AU7940182A (en) 1982-08-05

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